This invention relates to a portable device for supporting and guiding a working tool, for example a burning torch for the heat separation of material or a welding nozzle such as a semiautomatic welding arrangement operating in a protective CO.sub.2 atmosphere, and the like.
Actually known portable working devices, for example for the clamping and guiding of torches for burning by means of oxygen are of various designs. One of the known arrangements of such prior devices comprises a guiding rail along which a slidable support is guided by guiding rollers, the slidable support being provided with a drive by means of a pinion engaging a rack on the guiding rail. The torch is clamped on the supporting arm fixed on the slidable support.
A drawback of the above-described known arrangement is that the working range of the torch is limited by the shape of the rail, such rail being straight and extending in advance of the slidable support. The use of this arrangement in internal and external spaces of welded objects is frequently limited by the length of the guiding rail. Another drawback of such arrangement is that in case of an undulating or curved surface of the work piece deviations of the shape are encountered when making bevels bevels for weldings. The same drawbacks are encountered in the case of separating of material having a complicated surface, since the guiding rail, due to its rigidity, can not be readily deformed to follow such surface.
There is furthermore a known arrangement without a guiding rail wherein wheels of a bogie move along the the worked material with the possibility of being guided along rails. These arrangements are usually provided with two axles, one of which is a guiding axle, with a drive situated beyond both axles. The torch carried by the device is disposed beyond the axles of the traveling wheels of the bogie.
A drawback of this known arrangement is that in order to secure a sufficient thrust on the traveling wheels of the bogie to prevent their slipping upon the workpiece, the arrangement has to have a heavy weight; a consequence of this is a limitation of the manner of use of the arrangement to horizontal surfaces, and at most possibly the surfaces having a slight inclination with respect to the horizontal. The minimum length of this arrangement is at least twice the diameter of the traveling wheels. A consequence of this is the fact that the torches prevented from working upon a very considerable length of the track of operation of the arrangement.